From introduction: The purpose of this report is to present reateration-rate coefficients for the Rock River between Lake Koshkonong, Wis., and Rocktonm, Ill., for the annual minimum 7-day mean flow that occurs on the average of once in 10 years.

Abstract: The principal chemical, physical and biological characteristics, as well as the hydrology of Laguna Tortuguero, Puerto Rico, were studied from 1974-75. The lagoon, with and area of 2.24 square kilometers and a volume of about 2.68 million cubic meters, contains about 5 percent of seawater. Drainage through a canal on the north side averages 0.64 cubic meters per second per day, flushing the lagoon about 7.5 times per year. Chloride and sodium are the principal ions in the water, ranging from 300 to 700 mg/L and 150 to 400 mg/L, respectively. Among the nutrients, nitrogen averages about 1.7 milligrams per liter, exceeding phosphorus in a weight ratio of 170:1. About 10 percent of the nitrogen and 40 percent of the phosphorus entering the lagoon is retained. The bottom sediments, with a volume of about 4.5 million cubic meters, average 0.8 and 0.014 percent nitrogen and phosphorus, respectively.

"This report presents the hydraulic and chemical data collected at a deep-well waste-injection system near Pensacola, Florida." It includes maps, graphs, and tables.

From introduction: This report describes an alternative approach to developing flood frequency characteristics, and presents results of the application of that technique to small streams in the urban and sub-urban areas of Memphis, Tennessee. The tool used is a regression model, with variations. The use of a parametric rainfall runoff model is not attempted in the analysis.